1. Field of the Invention
The invention relates to an insulating mat for bodies of which the surface has at least portions which are curved, particularly pipes.
2. Background of the Related Art
Usually, what are referred to as pipe insulating shells are formed of mineral fiber material. Such pipe insulating shells are produced by wrapping a mineral fiber fleece incorporating a binding agent around a core, the outside diameter of which corresponds to the diameter of the pipe to be insulated, and hardening the mineral fiber material which is thus wrapped into a tubular form. This produces a shell body the shape of which is stable, which offers good heat insulating capacity and also comparatively high compression resistance. Insulated pipes, such as for example district heating pipes, which have been insulated by means of such pipe insulating shells, thus have a surface which is stable under compression and which can be subjected to a loading, and can, for example, be walked upon.
However, a disadvantage of such pipe insulating shells resides in the fact that they necessarily must be prefabricated for a specific diameter of pipe and can therefore only be used for such a pipe. This means that it is necessary to carry a wide variety of such pipe insulating shells, resulting in considerable stock-keeping expenses, and the freedom with which such insulating elements can be used is adversely affected. Furthermore, the pipe insulating shells which have to be prefabricated to their final shape also have to be stored and dispatched in this shape, resulting in considerable storage and transport bulk. Where these so-called solid shells are used, it is furthermore necessary that the pipe to be insulated be accessible from its end so that the solid shell can be pushed onto the pipe. In order to avoid this need, and also for subsequent insulation jobs, it must be possible to apply the insulating member from the side, a possibility afforded by using slotted solid shells, half shells or other suitable shell segments. In any case, the prefabricated form of the shell presents difficulties with insulation in confined spaces, such as shafts or the like, since the shells or shell segments are correspondingly bulky. Fitting of the pipe insulating shells onto the pipe to be insulated requires an inconsiderable freedom of movement in the immediate vicinity of the pipe, and this is often not available.
Furthermore, the ability to use pipe insulating shells is confined to pipes of circular cross-section, whereas the same kind of insulation is impossible, for instance, in the case of rectangular ducting.
For insulating surfaces of which at least parts are curved, so-called laminate mats are also known which are produced by applying individual strips ("laminate strips") of the mineral fiber material to a carrier web such as an aluminum mesh-lined film and solidifying the strips, the fibers of the individual strips being orientated in their preferred main direction at right angles to the plane of the carrier web. By fixing the strips on the carrier web, which is on the outside of the curvature, the width of the portions of the strips at the web is established, while the consistency of the strips is so chosen that with the radius of curvature envisaged, there is a correspondingly slight compression of the strips on the side opposite the carrier web.
The fibers are positioned more closely to one another transversely of their orientation and in this way the width of the strips is locally reduced without any substantial restoring forces and without distortion or kinking of the fibers. Therefore, the insulating mat acquires a flexurally soft character.
This offers the advantage that pipes of different diameters can be insulated with the same insulating product. Furthermore, components of different curvatures such as containers, air conditioning ducts, etc., can be insulated, the mat being adapted to any existing radius of curvature without difficulty.
However, pipe insulating shells cannot be replaced by laminate mats for all possible applications, because the laminate mats have a substantially lower compression loading capacity than pipe insulating shells so that they are suitable only for those applications in which only relatively low compression loading applies. The pressure loading capacity of the laminate mats cannot be easily increased either, since with increasing crude density and increasing binder content, the strips also become stiffer on the side opposite the carrier web so that they are no longer able to offer low-force compressibility to dissipate peripherally acting compression forces such as occur during adaptation to a radius of curvature.